1. Field of the Invention
The present invention relates to a connecting block for connection of a communication cable, and more particularly to a connecting block having a coupling pin for reducing crosstalk between pairs of terminal pines or alien crosstalk between connecting blocks.
2. Description of the Related Art
Generally, a connecting block having a plurality slots for the insertion of conducive wires and a plurality of terminal pins corresponding thereto is installed in a communication terminal box for the purpose of wiring of communication cables such as UTP cable.
A connecting block, known as ‘110 block’ in the art, includes an insulator housing and an IDC (Insulation Displacement Connection) terminal pin installed in the housing.
The housing is provided in a block form in which slots into which conductive wires of a communication cable may be inserted, are repeatedly formed at regular intervals. The housing is configured such that 8 slots are arranged in a line in correspondence with 4 pairs of conductive wires provided in the UTP cable.
The IDC terminal pin has a blade structure, which is diverged into two branches, such that, when a conductive wire of a communication cable is inserted therein, a coating of the conductive wire may be cut. The IDC terminal pin is installed to every slot formed in the housing, and each IDC terminal pin is arranged such that a groove with the blade structure diverged into two branches is accorded with the slot of the housing.
Generally, the connecting block is used in a state that a plurality of housings are connected in series on a base block.
However, in a conventional connecting block, crosstalk occurs between IDC terminal pins in the housing when a communication cable is connected thereto, and alien crosstalk occurs between IDC terminal pins of adjacent blocks, thereby causing loss of signal power.
To solve this problem, there have been proposed techniques of designing IDC terminal pins to have a sufficiently great gap or crossing IDC terminals in pair.
For example, U.S. Pat. No. 6,346,005 discloses that IDC terminal pin pairs have a great gap between them, and a barrier is added between the pairs for electric shielding.
U.S. Pat. No. 7,322,847 discloses a structure in which a lower end of each IDC terminal pin is offset from its upper end so as to cross IDC terminal pins of each pair from each other.
U.S. Pat. No. 7,121,870 discloses that a substantial capacitor structure is formed using an extending conductor between adjacent IDC pair to electrical couple the pairs.
However, the connecting system disclosed in U.S. Pat. No. 6,346,005 has a drawback in that an overall size of the block is seriously increased. Also, the connecting block disclosed in U.S. Pat. No. 7,322,847 has a drawback in that the structure of IDC terminal pin should be changed, resulting in back compatibility with existing products.
In case of the IDC terminal assembly disclosed in U.S. Pat. No. 7,121,870, the extending conductor used for coupling is integrated with IDC, so an assembling work is not easy. In addition, there is limit in that align crosstalk between blocks cannot be reduced. In addition, the IDC terminal assembly disclosed in U.S. Pat. No. 7,121,870 has a problem in that a capacitance value between each extending conductor and IDC is seriously changed depending on an assembling tolerance, thereby not ensuring constant coupling. It can be considered as an alternative to decrease an assembling tolerance. However, if the assembling tolerance is too small, an assembling work becomes very difficult and parts should be prepared with very precise dimensions.